Human impact on the environment In this lesson you will learn about: the biological control of pest species the use of GM crops as an alternative to using.

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Presentation on theme: "Human impact on the environment In this lesson you will learn about: the biological control of pest species the use of GM crops as an alternative to using."— Presentation transcript:

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Human impact on the environment In this lesson you will learn about: the biological control of pest species the use of GM crops as an alternative to using fertilisers and pesticides Success criteria Explain biological control of pest species works Explain how GM crops can be used as an alternative to fertilisers and pesticides

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Human impact on the environment The biological control of pest species Can you name any common pest species that damage plants? (aphids, scale insects) (rabbits, rats) Can you think of how these can be controlled without using chemicals?

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Human impact on the environment Biological control of pest species is when the pest species numbers are controlled without the use of chemicals. Instead a biological control method is used. Rabbits can become a problem for Landowners if numbers multiply too much. Why do you think this is? A solution is to introduce the virus myxomatosis which infects and kills many of the rabbits

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Human impact on the environment The biological control of plant pest species includes: Ladybirds to kill aphids and scale insects Caterpillar moths to kill cacti Why use these method instead of chemicals?

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Human impact on the environment The alternative is to use pesticides against the insects and plants. These chemicals can be harmful to non-pest species directly and in run-off into fresh water.

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Human impact on the environment GM crops can be used as an alternative to using fertilisers and pesticides. You have studied GM crops in a previous topic. How can GM crops be used instead of these chemicals?

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Human impact on the environment Drought resistance can be transferred to the GM crop which will give better growth in dry conditions Pest resistance will give enhanced yields for crops that might otherwise show a lesser yield

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Human impact on the environment There are differences of opinion about GM crops and there benefits. But remember to look at the science. There are a lot of GM crops and the science is relatively new.